Publishers
- Claye, Brown & Claye 1
- Clearview 1
- Clement Ingleby 1
- Clifton Books 1
- Climber's Club 2
- Clive Holloway Books 2
- Clwydian-Press 1
- Clymer 4
- CMG Publishing 5
- Co-Operative Printing Sociaty Limited 1
- Co-operative Wholesale Society 2
- Cobden-Sanderson 1
- Cobham Plc 1
- Cocorico 1
- Colin A Pomeroy 1
- Colin Baxter Photography Ltd. 1
- Colin Buchanan And Partners 1
- Colin Orchard 1
- Collection Parthenope 1
- Collectors' Books 1
- College St. Centenary Committee 1
- Collet's 1
- Collier Macmillan Publishers 1
- Collins 514
- Collins & Harvill 3
- Collins and Harvill 2
- Collins Clear-Type Press 96
- Collins Colour Camera Books 1
- Collins Lions 2
- Collins Voyager 1
- Collins Willow 3
- Colmans Foods 1
- Colnaghi And Co. 1
- Colnet 2
- Colorado Railroad Museum 1
- Colorgravure 1
- Colour Library Books 2
- Colour Library Direct 2
- Colourbox Publishing 1
- Colourpoint 2
- Colt Books 1
- Columbia University Press 5
- Combined Publishing 2
- Commission Of Conservation Canada 1
- Commonwealth Agricultural Bureaux 1
- Commonwealth Scientific And Industrial Research Organization 1
- Commonwealth War Graves Commission 2
- Company Of Stationers 1
- Compassverlag 1
- Compendium 1
- Comstock Publishing Associates 2
- Comstock Publishing Company Inc. 1
- Concord Publications Co. 1
- Connaissance Du Rail 4
- Consejo Superior De Investigaciones Cintificas 1
- Conservation Press 1
- Consiglio Nazionale Delle Ricerche 1
- Constable 11
- Constable & Co. Ltd. 20
- Constable & Company 1
- Constable and Company Ltd. 21
- Constable Young Books 3
- Constable Young Books Ltd. 1
- Contact Publications Limited 1
- Continuum 1
- Conway 2
- Conway Maritime Press 20
- Copernicus 1
- Coppenrath 1
- Copple House Books 1
- Corgi 1
- Corgi Yearling Books 1
- Cornell University Press 4
- Cornish Brothers Limited 4
- Cornmarket 1
- Cornstalk Publishing 1
- Cornstalk Publishing Company 1
- Corris Railway Society 1
- Costello 1
- Cote D'Or 1
- Coterie Press Limited 6
- Council For British Archaeology 1
- Council Of Museums In Wales 1
- Country & Sporting Publications 1
- Country Life 24
- Country Life Books 1
- Country Life Limited 17
- Country Life Ltd. 13
- Countryside Books 7
- Courage Books 1
- Coventry University Enterprises Ltd. 1
- Coward-McCann Inc. 1
- CP Press 1
- Crash Media Group 5
- CRC Press 3
- Crecy 2
- Crecy Books 2
- Crecy Publishing Limited 3
- Crescent Books 1
- Cricket Books 1